Pregnant Occupant Model Including a Fetus for Vehicle Safety Investigations

Computational occupant modelling has an effective role to play in investigating road safety. Realistic representation of occupants is very important to make investigations in virtual environment. Pregnant occupant modelling can help investigating safety for unborn occupants (fetuses) however, existing pregnant occupant models are not very realistic. Most do not anthropometrically represent pregnant women and do not include a fetus model. ‘Expecting’, a computational pregnant occupant model, developed with a view to simulate the dynamic response to crash impacts is briefly explained in this paper. The model is validated through rigid bar impacts and belt loading tests and used to simulate a wide range of impacts. ‘Expecting’, possess the anthropometric properties of a 5th percentile female at around the 38th week of pregnancy. The model is complete with a finite element uterus and a realistic multibody fetus which is a novel feature in models of this kind. In this paper, the effect of further developments to ‘Expecting’, by incorporating a finite element fetus head model is investigated. Further detailed anatomic geometry is used to generate deformable fetus head model. The model is used to simulate a range of frontal impacts with seatbelt and airbag, as well as no restraint cases. The strains developed in the utero-placental interface are used as the main criteria for fetus safety. The effect of incorporating a finite element fetus head in the pregnant occupant model is discussed.

Dynamic Behavior and Synchronization of an Automobile as a Complex System

A complex system is composed of many interacting components, but the behavior of the system as a whole can be quite different from that of the individual components. An automobile is an example of a common mechanical system composed of a large number of individual components that are mechanically connected in some way and hence transmit vibrations to each other. This paper proposes a variety of inter-related analytical tools for the study of experimental data from such systems. In this work, experimental results of accelerometer data acquired at two locations in the automobile for two different kinds of tests are analyzed. One test is the response to impact on a stationary vehicle, and the other is the road-response to the vehicle being driven on a flat road at different speeds. Signals were processed via Fourier and wavelet transforms, cross-correlation coefficients were computed, and Hilbert transforms and Kuramoto order parameters were determined. A new parameter representing synchronization deficit is introduced. There is indeed some degree of synchronization that can be quantified between the accelerations measured at these two locations in the vehicle.

Some Unexpected Results in the Stress Calculation Around Multiple Holes in an Isotropic Plate Under In-Plane-Loads

The Schwarz alternating method, along with Muskhelishvili’s complex potential method, is used to calculate the stresses around non-intersecting circular holes in an infinite isotropic plate subjected to in-plane loads at infinity. The holes may have any size and may be disposed in any manner in the plate, and the loading may be in any direction. Complex Fourier series, whose coefficients are calculated using numerical integration, are incorporated within a Mathematica program for the determination of the tangential stress around any of the holes. The stress values obtained are then compared to published results in the literature and to results obtained using the finite element method. It is found that part of the results generated by the authors do not agree with some of the published ones, specifically, those pertaining to the locations and magnitudes of certain maximum stresses occurring around the contour of holes in a plate containing two holes at close proximity to each other. This is despite the fact that the results from the present authors’ procedure have been verified several times by finite element calculations. The object of this paper is to present and discuss the results calculated using the authors’ method and to underline the discrepancy mentioned above.

Development of a Driving Cycle for Amman City With Performance Evaluation for ICE Vehicle

A good driving cycle is needed for accurate evaluation of a vehicle’s performance in terms of emission and fuel consumption. Driving cycles obtained for certain cities or countries are not usually applicable to other cities or countries. Therefore, considerable research has been conducted on developing driving cycles for certain cities and regions. In this paper, a driving cycle for a taxi in Amman city, the capital of Jordan, is developed. Significant differences are noted when comparing the Amman driving cycle with other driving cycles. A model of a gasoline powered vehicle is used to conduct a performance comparison in terms of fuel economy and emissions utilizing the developed Amman driving cycle and six other worldwide driving cycles. The developed Amman driving cycle is very useful in obtaining accurate estimation of fuel economy and emissions for vehicles running on Amman roads and will be used in future work to study the performance of hybrid fuel cell/ battery vehicles.

A Model for Organizing and Analyzing Integration of Environmental Concerns in Product Design and Re-Design

Based on examples from research and innovation within nanotechnology, housing, bioenergy, and clothing the complexity of environmental innovation is discussed. A model for a more holistic approach to environmental innovation, which can be used both as part of innovation processes and for analyses of previous innovation processes, is developed. The approach is based on: 1) A scenario perspective on environmental aspects and impacts which implies a focus on the future roles of a product, its users and the surrounding society as imagined by the designers in their considerations about the problems addressed by the product and the solution it is offering. 2) A system’s perspective which implies a focus on the system, which a product is part of, including the need for supporting infrastructures like stakeholder training, waste management etc. 3) A lifecycle perspective to environmental aspects and impacts in order not only to capture environmental aspects from cradle to grave, e.g. related to material extraction and refining, chemical exposure during manufacturing, use and waste handling. 4) A governance perspective on management of environmental aspects and impacts, both in relation to the legitimacy of the environmental problems addressed and the solutions ‘offered’ by the product.

Effect of Temperature Gradient on the Mechanical Buckling Resistance of FGM Shallow Arches

This work presents a closed form investigation on the effect of temperature gradient on the buckling resistance of functionally graded material (FGM) shallow arches. The constituents are assumed to vary smoothly through the thickness of the arch according to the power law distribution and they are assumed to be temperature dependent. The arches subjected to the both uniform distributed radial load and central concentrated load and both boundary supports are supposed to be pinned. The temperature field is approximated by one-dimensional linear gradient through the thickness of the arch and the displacement field approximated by classical arches model. Also, Donnell type kinematics is utilized to extract the suitable strain-displacement relations for shallow arches. Adjacent equilibrium criterion is used to buckling analysis, and, critical bifurcation load is obtain in the complete presence of pre-buckling deformations. Results discloses the usefulness of using the FGM shallow arches in thermal environment because the temperature gradient enhances the buckling resistance of these structures when they are subjected to a lateral mechanical load.

Reverse Engineering Using Close Range Photogrammetry for Additive Manufactured Reproduction of Egyptian Artefacts and Other Objets d’art

Photogrammetry has been in use for over one hundred and fifty years. This research considers how digital image capture using a medium range Nikon Digital SLR camera, can be transformed into 3D virtual spatial images, and together with additive manufacturing (AM) technology, geometric representations of the original artefact can be fabricated. The research has focused on the use of photogrammetry as opposed to laser scanning (LS), investigating the shift from LS use to a Digital Single Lens Reflex (DSLR) camera exclusively. The basic photogrammetry equipment required is discussed, with the main objective being simplicity of execution for eventual realisation of physical products. As the processing power of computers has increased and become widely available, at affordable prices, software programs have improved, so it is now possible to digitally combine multi-view photographs, taken from 360°, into 3D virtual representational images. This has now led to the possibility of 3D images being created without LS intervention. Two methods of digital data capture are employed and discussed, in acquiring up to 130 digital data images, taken from different angles using the DSLR camera together with the specific operating conditions in which to photograph the objects. Three case studies are documented, the first, a modern clay sculpture, whilst the other two are 3000 year old Egyptian clay artefacts and the objects were recreated using AM technology. It has been shown that with the use of a standard DSLR camera and computer software, 2D images can be converted into 3D virtual video replicas as well as solid, geometric representation of the originals.

A Study on a Grade-One Type of Hypo-Elastic Models

In Hypo-elastic constitutive models an objective rate of the Cauchy stress tensor is expressed in terms of the current state of the stress and the deformation rate tensor D in a way that the dependency on the latter is a homogeneously linear one. In this work, a type of grade-one hypo-elastic models (i.e. models with linear dependency of the hypo-elasticity tensor on the stress) is considered for isotropic materials based on the objective corotational rates of stress. A positive real parameter denoted by n is involved in the considered type. Different values can be selected for this parameter, each selection leads to a specific model within the class of grade-one hypo-elasticity. The spin of the associated corotational rate is also dependent on the parameter n. In the special case of n=0, the corresponding hypo-elastic model reduces to a grade-zero one with the logarithmic rate of stress; noting that this rate is a corotational rate associated with the logarithmic spin tensor. Moreover, by choosing n=2, the model reduces to a grade-one hypo-elastic model with the Jaumann rate, i.e. the corotational rate associated with the vorticity spin tensor. As case studies, the simple shear problem is investigated with utilizing the considered type of hypo-elastic models with various values for parameter n, and the curves for the stress-shear response are depicted.

Potential of the Variable Valve Actuation (VVA) Strategy on a Heavy Duty CNG Engine

The environmental concerns officially aroused in 1970s made the control of the engine emissions a major issue for the automotive industry. The corresponding reduction in fuel consumption has become a challenge so as to meet the current and future emission legislations. Given the increasing interest retained by the optimal use of a Variable Valve Actuation (VVA) technology, the present paper investigates into the potentials of combining the VVA solution to CNG fuelling. Experiments and simulations were carried out on a heavy duty 6-cylinders CNG engine equipped with a turbocharger displaying a twin-entry waste-gate-controlled turbine. The analysis aimed at exploring the potentials of the Early Intake Valve Closure (EIVC) mode and to identify advanced solutions for the combustion management as well as for the turbo-matching. The engine model was developed within the GT-Power environment and was finely tuned to reproduce the experimental readings under steady state operations. The 0D-1D model was hence run to reproduce the engine operating conditions at different speeds and loads and to highlight the effect of the VVA on the engine performance as well as on the fuel consumption and engine emissions. Pumping losses proved to reduce to a great extent, thus decreasing the brake specific fuel consumption (BSFC) with respect to the throttled engine. The exhaust temperature at the turbine inlet was kept to an almost constant value and minor variations were allowed. This was meant to avoid an excessive worsening in the TWC working conditions, as well as deterioration in the turbocharger performance during load transients. The numerical results also proved that full load torque increases can be achieved by reducing the spark advance so that a higher enthalpy is delivered to the turbocharger. Similar torque levels were also obtained by means of Early Intake Valve Closing strategy. For the latter case, negligible penalties in the fuel consumption were detected. Moreover, for a given combustion phasing, the IVC angle directly controls the mass-flow rate and thus the torque. On the other hand, a slight dependence on the combustion phasing can be detected at part load. Finally, the simulations assessed for almost constant fuel consumption for a wide range of IVC and SA values. Specific attention was also paid to the turbocharger group functioning and to its correct matching to the engine working point. The simulations showed that the working point on the compressor map can be optimized by properly setting the spark advance (SA) as referred to the adopted intake-valve closing angle. It is anyhow worth observing that the engine high loads set a constraint deriving from the need to meet the limits on the peak firing pressure (PFP), thus limiting the possibility to optimize the working point once the turbo-matching is defined.

Functional Recovery of the Upper Limb With an Active Personal Device

A new personal device to assist the upper limb capable to be mounted on a wheelchair is being tested. The robot is equipped with three brushless motors powered by four electronic boards appositely designed and communicating via I2C protocol; one board works as master for the other three, which have simpler tasks. Most of the driving software has been developed with Matlab and mainly translated into C++ for memory space and boards’ efficiency matters. The system’s end-effector is connected to the subject’s forearm and can cooperate to the arm motion in several different ways. In order to avoid the overstress of the natural joints no further connections are made to the upper limb. The working volume of the limb connected to the device allows the execution of the trajectories required for most of daily living activities. It is addressed to post stroke rehabilitation and to the self-treatment of other patients with serious deficiency of arm forces, like individuals affected by muscular dystrophy. Some working modes exploit the mechanical impedance control to gently interfere with the residual natural motion capability of the subjects. The very preliminary tests of the prototype fitted on a power wheelchair are encouraging: it is light, not too noisy and easy to move for the subject. The first working mode, with full arm gravity compensation, and the second working mode, with partial compensation, have been implemented and are currently being tested with patients, as well as the mode in which the subject is helped to repeat a stereotyped exercise for self-physiotherapy. Beside the fact the control system must be calibrated on patient characteristics, for these initial tasks the system reveals to be user-friendly. Other working modes require to interpret the patient intention to move the upper limb. For a natural approach it is sufficient to decode the movement intention of the patient and the final position he wants the hand to reach, whilst the rest of the limb can be automatically positioned by the system. Different approaches to solve the problem have been experimentally tested, including the use of a headgear with a brain interface. To present knowledge the best results have been obtained by monitoring the movement of another body segment such as the head. The device designed for the functional recovery of upper limb can furthermore be used to monitor and easily certify the evolution of the patient conditions.